The small three-core is generally a stereo unbalanced connector, which is different from the big three-core (mono balanced connector)
Both the big three-core and the XLR head are mono balanced connectors, because the interfaces of the mixers, terminals and other equipment connected to these two heads are monophonic, and the small three-pin is connected to stereo jacks such as computers and mobile phones.
The picture below shows the correct welding method, stereo connection (the same applies to big three-core, lotus head, and XLR head)
potential problem
1. Small three cores - Phoenix head
Phoenix has three cores, one of which is an independent shielding layer and does not participate in signal transmission, and the remaining two cores can correspond to the two cores of a certain channel in the traditional left and right channels.
2. Personal practice has proved that when the small three-core is soldered, the small three-core connectors are normally connected to + and -, and the opposite ends can occasionally be welded together with red and white. For example, the small three-core-two lotus heads-two lotus heads The signal wires are all connected red and white, and are normally grounded. (But maybe this connection is more versatile and reliable)
If the left and right channels are welded together, there will be no potential difference in the common parts of the left and right channels (such as human voice and low frequency), and the low frequency and human voice will basically disappear.
Connect the small three-core to the XLR one by one. When the XLR is output, the polarity of the right channel is reversed and the left channel is superimposed, which cancels out the same part. Usually, there are human voices in the left and right channels. If they are cancelled, they will disappear.
Precautions
1. Small three-core - large three-core adapter
It will convert stereo to mono, and the above-mentioned signal cancellation problem may occur when connecting devices
2. There is no relationship between binaural and balanced unbalanced connection
Why does the 3.5mm earphone automatically cancel the human voice when it is half plugged in or the contact is bad when listening to music?
Vocals are usually picked up in mono and split equally between the two channels.
In this way, the human voices of the left and right channels have the same phase and the same amplitude, and the differential voltage between them is 0 at this time.
When the earphones are slightly withdrawn, the ground wire (common end) of the earphones may not be in contact, so that the left and right earphones form a series connection, and are directly connected to the output terminals of the left and right channels, while the human voice is in the left and right channels. The differential voltage is 0, so the human voice is "cancelled".
Other soundtracks are originally multi-channel pickups, and the received signals will be somewhat different. In the end, the difference between the left and right channels will not be 0, so these sounds can still be heard.